Sheet metal fluid pressure storage vessel and method of forming the same



v Aug. 14. 1956 P s. DOUGHERTY 2,758,367

SHEET METAL ELUID PRESSURE STORAGE VESSEL AND METHOD OF FORMING THE SAMEFiled Aug. 1, 1952 2 Sheets-Sheet 1 Aug. 14. 1956 P. s. DOUGHERTY2,758,367

SHEET METAL FLUID PRESSURE STORAGE VESSEL AND METHOD OF FORMING THE SAMEFiled Aug. 1, 1952 2 Sheets-Sheet 2 L-All! I /5- I l I i /5 I ,f azz@Jazz %6/7, 40 80 Ej@ SHEET NETAL FL PRESS STGR'AGE VES- SEL AND METHODOF EGG THE S Paul S. Dougherty, La Grange, 11L, assignor to ivietalCoating Corporation, a corporation of lliinors Application August 1,1952, Serial No. '3ll2,189

1 Claim. (c1. 29-446) This invention relates to a sheet metal fluidpressure storage vessel and method of assembling the same and moreparticularly to household Water tanks and the like.

The vessels to which the present invention is primarily related are madeup of sheet metal, usually sheet iron. In the case of water storagetanks, the guage or" the metal is usually 8 to 9. In high pressurevessels, the gauge may be as low as 3 1 inch) and in some cases thegauge may be as high as 12.

In the case of water storage vessels, the steel is normally galvanizedand the present invention is well adapted to hot galvanizing afterassembly of the vessel.

The usual storage vessel of this type is generally cylindrical and iscomposed of a generally cylindrical shell, a head and a bottom. In theprevious constructions, the head and bottom have been of smallerdiameter than the shell and nest inside it. It is obvious that a tightfit is necessary and with the gauges employed the metal is so rigid thatthe insertion of the heads and bottoms requires a great deal of manuallabor and even then the fits secured are such that after welding it hasheretofore been considered normal to have a very large proportion ofleaking tanks which have to be mended before use.

The vessel is adapted to be assembled on automatic hydraulic machineryupon which it may be welded whiie held in position. I have foundassembly may be made very easy, providing shell and bottom are offset toprovide a shoulder upon each which serves as an automatic stop uponpressure assembly of the vessel and likewise provides an area ofdefinition for a circular weld automatically performed while held inpressed relationship.

The invention is illustrated in the drawings in which:

Figure 1 is a diagrammatic illustration of the assembled vessel held inpressure relationship in a hydraulic apparatus wherein it may be welded;

Figure 2 is a side elevation of the pressure storage vessel;

Figure 3 is a plan view of the top;

Figure 4 is a plan view of the bottom;

Figure 5 is a detailed fragmentary vertical sectional view of the headconstruction;

Figure 6 is a similar View of the detail of the bottom construction;

Figure 7 is a fragmentary vertical sectional elevation aftergalvanization and welding; and

Figure 8 is a vertical sectional view of a bottom before formation ofthe shoulder.

As shown in the drawings, the vessel comprises a gen erally cylindricalsheet metal shell 14 which is provided with a relatively small crimpedarea which forms the flange 11 at the top which provides a shoulder 12.The depth of the shoulder 12 is approximately the thickness of the metalin the head 13. The head 13 is a domed sheet metal cap Whose exteriordiameter is substantially that of the shell and whose interior diameteris the same as the outer diameter of the flange 11.

The head is provided with openings 14 which may serve as pipeconnections. The shell is likewise provided with 1 atnt i 2,758,367Patented Aug. 14, 1956 a suitable number of openings 15 which serve forsuitable pipe connections.

The bottom 20 comprises a sheet metal structure of substantially thesame thickness as the head of the vessel. It has a web portion 21 and ashort, downwardly depending flange 22. The web is usually dishedinwardly or outwardly. At the bottom this flange is flared outwardlyforming a shoulder of about the same depth as the thickness of the shell10. A terminal flange 24 extends downwardly from the shoulder 23. It is,of course, obvious that this flange may be eliminated if desired or maybe cut 013? after formation of the vessel. Normally, it is preferred notto do so.

The formation of the bottom is important. It has not been foundsatisfactory to produce a cylindrical bottom and then crimp the upperportion thereof to provide the shoulder 23. Efiorts have been made to dothis over a long period completely Without success. I have found,however, that the bottom may very simply be produced in the mannershown. Figure 8 shows the bottom before formation of the shoulder andindicates in dotted line its shape after formation. This is produced byuse of an upsetting die by which the shoulder 23 and the flange 24 areoffset outwardly from the main body of the metal.

After the bottoms have been formed as indicated in Figure 8, the top,shell, and bottom are aligned in the hydraulic machine 30 and pressureis applied so that the elements are telescoped together to take the formshown in Figure 2. In this operation, the bottom of the flange 16 of thetop is brought against the shoulder 12 which serves as a stop as well asan aligning means so that the top is properly and evenly aligned withthe shell. Similarly, the bottom of the shell is brought against theshoulder 23 which serves as a stop and aligning device for bringing thebottom and shell into proper relationship.

When the assembly has been completed, the elements are welded togetherwhile held in the machine, the elements being rotatable therein and thetwo welds being applied by automatic means operating simultaneouslywhile so held and rotated. The preferred welding is by submerged arc.The welds are indicated at 40 and 41 in the groove or valley formedbetween the ends of the top and bottom and their respective shouldersengaged thereby as clearly shown in Figures 5 and 6.

After the welding has been completed, the vessel is galvanized by thehot method. The entire vessel is submerged in the molten zinc bath,submergence being through a portion of the bath which has a layer ofmolten flux on its surface. The flux enters the openings 14 in the topof the vessel and also the drain plug opening 42 in the bottom as wellas the openings 15 in the shell. After immersion, the vessel iswithdrawn and drained, preferably while being held in upside downposition so that the surplus molten metal will be exhausted through thevarious openings and particularly through the openings 14. The enlargedview of Figure 7 shows a layer of galvanizing 45 on both the inside andoutside of the tank at the juncture of the head 13 and shell 10.

It is important that the flanges 22 and 11 of the bottom and shellrespectively be tapered and that the outermost portion of the taper ineach case be slightly more than the internal diameter of the shell. Inthis way, a tight fit is secured all the way around and air pockets areavoided which might cause difiiculty in the welding. It is alsoimportant that the slope and length of this flange be identical in allcases so that the position of successive pressure vessels on thehydraulic machine shall be identical; otherwise, it is necessary toadjust one or more of the welding heads.

It will be noted in Figure 1 that the welding heads 50 may be mounted inpermanent adjustable position above 3 the vessel. The heads may be movedfor work on different sized vessels and once set, will need very littlefurther adjustment.

In carrying out the welding operation, the grooves between the head andthe shell and between the shell and the bottom are utilized as thefillet grooves for the weldifig operation, thus avoiding the necessityof grinding or otherwise forming these grooves.

In assembling the device in the hydraulic machine, a pressure of severaltons may be employed to bring the portions of the assembly into properalignment. This pressure is maintained during the entire Weldingoperation and avoids the distortion or skewing which normally takesplace in the welding of such vessels.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom as modifications will be obvious to those skilled in the art.

I claim: V

The method of assembling a sheet metal pressure storage vessel composedof a shell, a head, and a bottom constructed to fit togethertelescopically which comprises the steps of, reducing one end of a metalcylindrical shell to provide an annular shoulder and an end portionhaving an outside diameter approximately that of the inside diameter ofthe shell, forming a cap-like head having an inside diameter equal tothe outside diameter of the reduced end of the shell and an outsidediameter equal to the outside diameter of the major portion of theshell, forming a bottom with a circular web portion and an annulardepending flange having an outside diameter substantially equal to theinside diameter of said shell, upsetting said flange to provide anannular shoulder and a further depending flange having an outsidediameter equal to the outside diameter of the major portion of theshell, positioning said head, shell and bottom in disassembled alignedrelationship in the order in which they fit together, applying pressureaxially of the elements to telescope them together a predetermineddistance to said shoulders and to their final positions, andsimultaneously rotating and welding the head and bottom to the shellwhile maintaining the axial assembling pressure.

References (iited in the file of this patent UNITED STATES PATENTS150,922 Wicesbrock May 12, 1874 489,644 Tripp Jan. 10, 1893 621,540Reynolds Mar. 21, 1899 1,097,744 Avery et a1 May 28, 1914 1,921,241Priebe Aug. 8, 1933 2,313,393 Mitchell Mar. 9, 1 943 2,350,720 BrodieJune 6, 1944 2,459,954 Morgan Jan. 25, 1949 2,517,853 Eickmeyer Aug. 8,1950 2,551,484 Branning May 1, 1951 2,613,015 Keating Oct. 7, 1952FOREIGN PATENTS 43,457 Austria Aug. 10, 1910 677,974 Great Britain Mar.12, 1952

